Intel 925XCV MB (PCI-E)

I BOUGHT THIS MB 10 DAYS AGO. EVERYTHING IS RUNNING FINE EXCEPT: IN IDLE MODE THE CPU TEMP (PRESCOTT 3.4 GHZ) IS AT 48c (FINE TO ME) SYSTEM ZONE 1 (IN MY MB ITS NEAR THE RAM DIMMS) IS AT 39c (ALSO FINE) AND FINALLY SYSTEM ZONE 2 TEMP IS GOING UP AND DOWN LIKE CRAZY...
I AM USING INTEL'S ACTIVE MONITOR.

I.E. : 39,42,41,49,38,52 (OVER THRESHOLD MESSAGE).

SOMEHING MUST BE WRONG. IS THE SENSOR BAD? IT CAN'T REALLY GO UP AND DOWN IN EVERY SEC!! NOTE THAT I HAVE THE LATEST BIOS RELEASE (JANUARY 05).
WHEN RUNNING A GAME THE SYSTEM ZONE 2 TEMP GETS NORMALLY UP BUT THE UP AND DOWNS ARE NOT SO HIGH (+3 -3 MAX).

WHAT DO YOU SUGGEST? DO I HAVE TO RETURN THE MB?
CAN MY PC AUTOMATICALLY SHUT DOWN BECAUSE THIS
SENSOR IS REPORTING WRONG TEMPERATURES??

P4 Zone 1 or Zone 2 temp fluctation

I have a intel D915GAG motherbroad running P4 530 3 GHz.
Using intel's monitor program (downloaded from intel's website).

No matter 915 or 925... I think almost the same principle.
For my PC, the temp of CPU, Zone 1 & Zone 2 varies +/- 1.5 C during low loading or high loading.

Thermal sensing diode has V-I characteristic curve (Current vs voltage gragh) which depended very much on temperature. i.e. the curve position drifts to left when temperature goes up. Other words, a change of V and I reflected a change in temperature. (Usually the detection circuit uses a "constant current source" to run through the diode and then monitor the voltage change against the temperature change. The relation between voltage change and temperature change is therefore obtained. There is factors like electrically noises etc. Equally saying, the temprature readings suffer from fluctation due to noises and ripples. (you have a SMPS as a power source) Besides, no perfect diode (expensive!), different diodes have slightly different characteristics therefore the calibrations persists errors (unless you calibration EACH diode inpendently during manufacturing! [cost])

(An alternative tempature measurement is using Thermocouple method which is more reliable [cost again])

I believe in this case, the readings of +/-4 C away from the ture value is normal. And temperature fluctation within +/-2 C is normal. When temperature increases you would possibly get a fluctation of +/-3 C. But if a jump of +/-5 C within seconds is highly impossible. Maybe you 'd better ask the supplier about your zone temperature finding.